AFFO is not even a remote benchmark to estimate taxable income which is where the 90% is applied. Can't do it from the income statement either.
With 92 cents as the midpoint of estimated per share cash flow available to common, 18+19+20+21 = 78 cents paid in calendar 2013. 78/92 = 84.8% payout ratio.
I believe Hamo is on a penny per quarter path. I'm very convinced of 19 in May and 20 in August because Hamo wants to thump his chest over doubling the dividend in two years. See my post on this going out more on IV board.